GB2332900A

GB2332900A - Easy-tearing packages

Info

Publication number: GB2332900A
Application number: GB9819497A
Authority: GB
Inventors: Luen Sing Tang
Original assignee: Tecksom International Ltd
Current assignee: Tecksom International Ltd
Priority date: 1998-01-05
Filing date: 1998-09-07
Publication date: 1999-07-07
Also published as: GB9819497D0; GB2332899A; TW359652B; GB9800118D0

Abstract

Packages comprising a sheet of easily-tearable flexible material having an outer layer and an inner layer, the inner layer being provided with a line of weakness. The line of weakness is preferably a perforated line in the inner layer, a zone which is thinner and weaker than the rest of the inner layer, or the interface between two abutting strips of material which are part of the inner layer. The inner layer may be attached to the outer layer along the line of weakness. The line of weakness in the inner layer of the sheet of flexible material acts as a natural guide during tearing of the material. In order to facilitate the initiation of a tear, the line of weakness typically has a nick at one end. The packages may include a number of internal compartment and are suitable for all types of goods, including drinks and pills. A drinking straw may be included in the package. The package may be a blister pack, Figure 13(c).

Description

1 EASY TEARING PACKAGES 2332900 This invention relates to material which

can easily be tom, without the need for scissors, for instance.

The waterproof, air-tight and durable nature of plastic bags means that they are widely used for packaging goods. Various ways for facilitating the opening of such bags are known. The simplest approach is to print a line on the bag to indicate where an opening should be cut. This cut might open directly onto the contents of the package (eg. Figure 1) or it might open onto a spout integrated into the package (eg. Figure 2; see also US patents 4491245, 4793121 & 4935283 and the "AmpacTm spout-pack"). Such a spout also makes a convenient opening for the insertion of a drinking straw.

Bags are also available which can be opened without the need for scissors. Whilst this can be achieved very easily by simply perforating the intended opening, this is not suitable where the package must be kept air- tight (eg. liquids or perishable goods). To overcome this difficulty, it is known to integrate a guide wire or string into a package which, when pulled, opens the package (eg. Figure 3). Another system incorporates two strong parallel tracks into the plastic which define a channel between them (eg. Figure 4). The end of this channel typically contains a nick in the plastic. When tearing begins at this nick, the two tracks guide the tear down the channel, giving a straight tear.

USA patent 5,552,202 describes an arrangement for guiding a tear which utilises bonded strips of materials which differ in stillness. This difference assists the breaking of the bond between the strips and guides a tear along the bond.

GB patent 1,147,846 describes how a thin strip incorporated in the body of a sheet can provide a guide for tearing. The thin strip may be either weaker or stronger than the body of the sheet. In the former case, the strip provides a weaker path through the film than the surrounding body, along which a tear is guided; where the strip is stronger, the strip can be easily tom out of the body of the sheet thereby separating the sheet in two.

In GB patent 1,335,036, a tear is guided by incorporating a flexible reinforcement across a sheet of material. This reinforcement itself contains a localised line of weakness and a tear along the like of weakness is transmitted to the attached sheet of material- 2 These tearing systems can also be integrated into re-sealable bags. Once the tear has been made, the bag can still be re-sealed by means of a zip- lock, for instance (eg. Figure 5). This gives a tamper-proof re-sealable bag.

It is an object of the invention to provide further means for facilitating the tearing of a sheet of packaging material. It is a further object to provide various types of package which can be opened easily, and also to provide easy-tear materials and packages which can be manufactured at relatively low cost.

According to the invention, there is provided a package comprising a sheet of easily-tearable flexible material having an outer layer and an inner layer, the inner layer being provided with 10 a line of weakness.

The line of weakness in the inner layer of the sheet of flexible material acts as a natural guide during tearing of the material ("tearing line'), and can take various forms. For example, the line of weakness may be a perforated line in the inner layer. In such a case, the individual perforations in the inner layer need not be circular in shape. It might, for instance, be a dot-dash perforation, or any interruption in the inner layer which substantially disconnects the two portions either side of the line of weakness. As an alternative, the line of weakness may be a zone which is thinner and weaker than the rest of the inner layer. Furthermore, the line of weakness may be the interface between two abutting strips of material which are part of the inner layer (eg. see W098/16382).

It will be apparent that, where a perforated or thin line is used to form the line of weakness, the inner layer will typically be formed from a single sheet of material. Where abutting strips are used, however, the inner layer may be formed from different abutting materials which together form the inner layer.

In preferred embodiments, the line of weakness is substantially straight. It is particularly preferred that the line of weakness should be the interface between two abutting strips of material which are part of the inner layer.

In order to facilitate the initiation of a tear, preferred embodiments include a small opening, break, nick, notch or the like at one end or both ends of the tearing line. Furthermore, the tearing line may be visibly indicated on the bag, for example by printing a dotted line at the 30 relevant position.

3 Being situated in the inner layer, rather than the outer layer, the tearing line is less likely to break or split due to any internal pressure exerted by contents of the package. In addition, the tearing line is protected from external damage such as rubbing.

It will be appreciated that the relationship between the "inne?' and "oute?' layers is defined with reference to the contents of the package ie. the inner layer is closer to the contents than the outer layer.

The inner layer of the flexible sheet is preferably attached to the outer layer of the flexible sheet along substantially the complete length of the fine of weakness.

The outer layer of the sheet of flexible material can be formed from anything that can be tom. 10 It can thus be formed from, for instance, plastic, paper, metallic film etc.

The inner and outer layers of the flexible material in the package are preferably of the same size or area ie. the layers extend across the whole area of the flexible material- This is not the case, for instance, where the inner layer is formed from a band of perforated material, or two bands of abutting material, attached to the outer layer In its minimum form, therefore, the invention provides a package comprising a two-layered sheet of easily-tearable flexible material, with the inner layer of the material containing a line of weakness. The sheet of flexible material may, however, comprise additional layers. For example, the outer layer of the sheet of flexible material need not be the outermost layer of the package; nor need the inner layer be the innermost layer of the package.

Indeed, it may be desirable to ensure that the tearing line is not exposed to the contents of the package, for instance by adding a flu-ther layer to the flexible material. Furthermore, if the sheet of flexible material is to be thermally bonded to another material, it is preferred that it includes an additional layer which protects the tearing line from being sealed itself This additional layer could, for instance, be heat- sealable at a temperature substantially below that 25 required to melt the layer of material containing the like of weakness.

Sheets of flexible material for use in the manufacture of packages according to the invention can be produced in a number of ways. Where the line of weakness in the inner layer is a perforated line, the material can be formed simply by bonding two sheets of flexible material, one of which contains a perforated line. Alternatively, a thin band of 30 material containing a perforation could be attached to a sheet of flexible material.

4 Similarly, where the line of weakness is a thin zone in the inner layer, the material can be formed by bonding two sheets of flexible material, one of which contains a thin zone.

International patent application W098/16382 describes how a plurality of strips may be placed in abutting relationship in plastic laminates. The interface between abutting strips forms a line of weakness. With reference to the two-layer laminated material described in W098/16382, layer 'W' can form the outer layer of the flexible material used in the present invention, and layer "C" (formed from abutting strips) can form the inner layer.

The strips which make up layer "C" may be made from the same or different materials, as set out in W098/16382 (eg. alternating transparent and opaque strips, such as holographic or metallised strips). It will be appreciated that where two abutting strips are of the same material, they can be formed by cutting a sheet of material into two before laminating to the outer layer; where they abutting strips are of different materials, however, they will typically be supplied from separate supply rollers.

Furthermore, layer "E" in the three-layer laminate of W098/16382 can form a layer additional to the inner and outer layers of the flexible material of the package of the present invention, as described above eg. to protect the tearing line from the contents of the package or during thermal bonding. Figure 6 shows an example of a suitable sheet of material comprising three layers.

It will be appreciated that, unlike the tear-guiding materials disclosed in the prior art, the present invention does not require any additional or special material to be incorporated into the package in order to guide the tear, as the line of weakness is integral in the packaging material. Thus, there is minimal additional production costs. For example, a line of weakness can be formed simply by cutting the inner layer into two pieces, or by introducing a perforation or thin zone, before bonding to the outer layer - no extra material is required.

Furthermore, the present invention does not rely on any difference in mechanical strengths of the materials either side of the line of weakness. Nor does the line of weakness "enable" tearing of the package - the outer layer is made of tearable material, and the line of weakness serves to control or guide the tear along a predetermined route.

In addition, the inner and outer layers of material which are used in the packages of the 30 invention may be made from any suitable flexible materials (eg. plastics, paper), provided that the outer layer is tearable and the inner layer includes a line of weakness.

i 1 The packages of the invention can take various forms, all of which utilise "a sheet of easily-tearable flexible material having an outer layer and an inner layer, the inner layer being provided with a line of weakness", hereafter simply an "easy-tear sheet" These packages will typically be over-printed with a design or pattern.

An easy-tear sheet may, for instance, be attached to a sheet of nontearable material and scaled to form a package which can be opened along the tearing line of the easy-tear sheet. For example, the invention provides a bag having a easy-tear front sheet and a non-tearing back sheet, sealed around the edges.

Where the line of weakness is the interface between abutting strips, the invention thus 10 provides a bag with a front and a back, with two abutting strips of material situated between the front and the back, the line of abutment constituting a tearing line.

Alternatively, an easy-tear sheet may be attached to another easy-tear sheet eg. a bag can be formed having a front and a back both formed from easy-tear sheets. These two sheets can be positioned such that the tearing lines in the two sheets are aligned (ie. essentially co-linear, but possibly deviating slightly eg. within 1 nun), thus ensuring that the tear in the front and back sheets of the bag are also aligned. The bag of the invention may thus comprise more than one layer of abutting strips between the front and the back eg, one in the front easy-tear sheet and one in the back.

Bags of the invention can also be produced by folding a single easy-tear sheet back on itself In addition, bags according to the invention may incorporate means for re- sealing an opened bag, such as a zip-lock. In such embodiments, the easy- tear line should be straight.

Packages and bags of the invention are preferably sealed around the edges. Whilst it is preferred not to seal along the full length of the tearing line, since this could result in the package remaining sealed even after being tom "open', the package may be sealed across the tearing line beyond that necessary simply to seal the edges of the package. When such a package is tom open, rather than becoming completely open, a smaller opening is exposed which allows the contents of the package to be poured more easily, in the same way as a spout. After opening, the contents of the package may be sucked or squeezed out. The spout may also be of a size and shape which allows it to be plugged.

6 As well as being suitable for pouring, the spout-like opening can also accept articles such as drinking straws, pipes, pumps etc. These may be included within the sealed package where appropriate eg. the sealed package may include an integral drinking straw such that, when the package is tom open, the drinking straw is already immersed and ready for use. The immersed drinking straw can preferably be extended after the package is tom open.

In packages containing an immersed drinking straw, the line of weakness will typically be substantially straight, and will guide the tear away from the portion of the package containing the beverage, in order to avoid spillage.

Placing a drinking straw inside a package together with a beverage offers a number of advantages eg. production costs are lower, because the straw is not packaged separately; the straw will not be lost inadvertently; the straw is more hygienic, as it cannot be contaminated after it is packaged.

Packaging a drinking straw in situ with a carbonated beverage in particular offers advantages over conventional carbonated beverage packages (ie. plastic bottles and cans).

Although still beverages, such as orange juice, are often distributed in packages which are punctured by drinking straws in order to access the beverage, this form of packaging is not suitable for carbonated beverages - due to the sudden pressure change when the package is punctured, the carbonated drink is forced out of the package through the straw, causing spillage. In the packages of the present invention, however, when the package is tom opened along the tearing line, the in situ drinking straw provides a buffer zone allowing the internal and external pressures to equilibrate, thereby preventing spillage. As no puncturing operation is required, the problem of spillage caused by sudden pressure change is avoided or minimised. Furthermore, flexible packages for carbonated beverages offer advantages over traditional hard containers such as production cost, storage space and cost when empty, transportation space and cost when empty, and environmental concerns.

Similarly, packaging a straw, tube, or other opening within a sealed package, such that the contents can leave the package via the straw or tube, offers hygienic advantages in other situations eg. medical situations, where the contents of the bag and straw/tube can both be packaged in sterile conditions. When the bag is tom open, the contents can be accessed easily, without the need to introduce a potentially-contaminated straw/tube from an external source.

i i 7 The sheets of flexible material used to produce packages of the invention may comprise more than one line of weakness. Where a sheet comprises two parallel lines of weakness, for instance, the sheet is, in effect, divided into three strips, the middle of which may easily be removed. The easy-tear sheet may thus be in the form of a cover for a package, a strip of which can be tom away to give access to the contents of the package. Each pair of tearing lines allows a separate strip of the sheet to be removed, each of which can give access to a different region of the package.

The package may contain a plurality of separate internal compartments. If a tearing line crosses the partition between two separate compartments, both compartments can be opened with one tear. If it is desired to halt the tear between opening successive compartments, this can be achieved by, for instance, providing a slight break in the tearing line.

Furthermore, means for assisting the removal of portions of the bag which have been opened may be incorporated. For instance, if perforations are included which are within the partition between two compartments and which cross the tearing line, the tear will tend to halt when it meets the perforation, and the torn part of the package can be removed by tearing along the perforated line, rather than along the tearing line. Alternatively, in certain embodiments, the perforated line could be tom first, stopping when the tearing line has been crossed, followed by tearing along the line of weakness. In this case, the junction between the perforation and the tearing line acts as a nick for facilitating initiation of the tear. Where a tear starts from the edge of the package, the tear can still be initiated, although a little more force may be required.

Packages of the invention are also suitable for storing liquids, such as beverages. In a preferred embodiment, the package of the invention comprises a first and a second sealed internal compartment. The first sealed internal compartment contains a drinking straw, which can be accessed by removing a portion of the package along the package's tearing line. The second sealed internal compartment contains a beverage. The beverage is not accessed via the tearing line used to access the drinking straw, however, but by puncturing the package using the drinking straw. Thus the package contains a beverage and a drinking straw., with the straw is stored in sanitary conditions within the package, preventing its inadvertent loss, but separate from the beverage. In addition, the tear is guided without tearing the package such that the beverage spills. This approach to packaging a drinking straw is a less-preferred alternative to the "immersed straw" approach described above.

8 The invention will now be described by way of examples, with reference to the accompanying drawings, in which: Figures 1-5 illustrate systems used in the prior art for facilitating the opening and re-sealing of bags; Figure 6 illustrates a laminated plastic material which can used to make packages according to the invention; and Figures 7-14 illustrate packages of the invention and their manufacture.

In a first embodiment, shown in Figure 7, using the methods described in W098/16382, a laminated plastic material was produced comprising two layers [Fig. 7(a)]:

-a parent base; and - a second layer consisting of two abutting parallel strips, one being a thin metallised strip and the other being a wide transparent strip.

A sheet of this material was aligned with a sheet of strong polythene [Fig. 7(b)], and these two sheets were sealed around all four edges to form a bag [Fig. 7(c)]. At the end of the interface between the two abutting parallel strips (ie. the end of the tearing line), a small nick was made. This bag can be opened easily without the need for scissors [Fig. 7(d)].

The tear along the polythene sheet in this type of bag is guided by the tearing line in the laminated material. As the bag is filled, however, the unsealed areas of the front and back of the bag are separated. In order to ensure that the tearing line in the laminated material is sufficiently close to the polythene sheet so that it is still able to guide a straight tear, it is preferred to minimise this separation by sealing the sheets up to or close to the tearing line.

In a second, less preferred embodiment, the nick was made before the two sheets were sealed, but only in the transparent base. This can be opened, but the back of the bag, formed from the polythene sheet, is not tom. This kind of bag is not preferred- In a third embodiment, shown in Figure 8, using the methods described in W098/16382, a laminated plastic material was produced comprising three layers:

a transparent base; a middle layer comprising two abutting parallel strips, one being a thin metallised strip and the other being a wide transparent strip; and -a parent top layer over-printed with a coloured pattern.

9 Two sheets of this material were stacked together, ensuring that the interface between the metallised and transparent strips were aligned [Figure 8(a)l. Three edges of the materials were then heat-sealed, as shown in Figure 8(b). The bag was then filled with contents and the fourth edge was sealed [Figure 8(c)]. A nick was then made on one edge at the interface 5 between the metallised and h-ansparent strips. This nick can be used to initiate the opening of the bag by tearing to release its contents [Figure 8(d)].

In a fourth embodiment, rather than using two separate sheets, the bag was formed by folding one sheet into two, whilst still ensuring that the interface between the metallised and tt-ansparent strips are aligned.

In a fifth embodiment, shown in Figure 9, the sealing procedure for the fourth edge of the bag was altered. The sealed area was extended across the tearing lines, except for a small gap [Figure 9(c)]. When this package is tom open, this small gap forms an opening [Figure 9(d)]. This opening allows the contents of the package to be poured more easily, in the same way as a spout, and also makes a convenient opening for a straw or pump [Figures 9(e) & (f)]. This gap may be plugged [Figure 9(g)]. The straw may also be included in the sealed package, immersed in the contents [Figure 9(h)], such that the straw is ready for use as soon as the package is opened [Figure 9(i)]. The straw can preferably be extended after the package is opened. This is especially useful for carbonated beverages.

In a sixth embodiment, shown in Figure 10, a zip-lock was incorporated during manufacture to give a re-sealable bag.

In a seventh embodiment, a bag similar to that shown in Figure 7 was produced, but was sealed internally along its length, crossing the tearing line [Figure 11 (a)], thus creating a multi-compartment bag. As this bag is tom open, compartments A, B and C are opened in series. With one tearing motion, these three compartments are opened essentially simultaneously. If the tearing motion is punctuated, however, then the compartments can easily be opened one-by-one. For instance, by stopping the tearing motion before it is completed, compartments A and B can be opened, whilst compartment C remains sealed [Figure 11 (b)l. To assist this, perforations were included within the sealed regions of the bag, as shown [Figure 11 (c)]. As this bag is tom open, the tear is naturally retarded at the first perforated line, resulting in compartments B and C remaining sealed whilst compartment A is opened. The opened portion of the bag can be tom off along the perforated line [Figure 11 (d)]. As an alternative, the perforated line could be tom first, as shown in Figure 1 1(e), followed by a tear along the line of weakness.

In an eighth embodiment an alternative multi-compartment bag was produced. A sheet of laminated material was produced comprising three parallel strips [Figure 12(a)], the middle of which was holographic. This was aligned with a sheet of polythene and these were sealed around their edges, and also internally, perpendicular to the tearing lines. Nicks were introduced at the ends of the tearing lines [Figure 12(b), showing a bag with three compartments]. By removing the holographic strip, the compartments are opened in series [Figure 12(c)]. As before, by incorporating perforations along the internal seals, the 10 compartments can easily be opened one-by-one [Figure 12(d)].

In a ninth embodiment, this design was adapted to make a multicompartment package particularly suitable for tablets or pills. This multi-compartment package is essentially three of the eighth embodiment packages placed side-by-side [Figure 13(b)]. As an alternative to using a sheet of polythene as the backing sheet [Figure Offl], a pre-formed blister-pack can 15 be used [Figure 13(c)j.

In a tenth embodiment [Figure 14], a package was formed containing two internal compartments. When this package is torn open, only one compartment is accessed, and the other remains sealed. When the package was sealed, the compartrnent which is opened by tearing included a drinking straw. After tearing the bag open, the drinking straw can be 20 removed and used to puncture the second sealed compartment.

It will be understood that the invention is described above by way of example only and modifications may be made whilst remaining within the scope and spirit of the invention.

i 1 11

Claims

1. A package comprising a sheet of easily-tearable flexible material having an outer layer and an inner layer, the inner layer being provided with a line of weakness.

2. A package according to claim 1, wherein the inner layer is attached to the outer layer along the length of the line of weakness.

3. A package according to claim 1 or claim 2, wherein the inner and outer layers are of the same size.

4. A package according to any preceding claim, wherein the line of weakness is a perforated line in the inner layer or a zone which is thinner and weaker than the rest of the inner 10 layer.

5. A package according to any one of claims 1 to 3 wherein the line of weakness is the interface between two abutting strips of material which are part of the inner layer.

6. A package according to any preceding claim, comprising a nick at one end or both ends of the line of weakness.

7. A package according to any preceding claim, wherein the sheet of flexible material comprises additional layers.

8. A package according to any preceding claim, wherein the sheet of flexible material is attached to a second sheet of fle3dble material which is, optionally, also provided with a line of weakness.

9. A package according to any preceding claim, containing a drinking straw.

10. A package according to clam 9, wherein the package contains a beverage.

11. A package according to claim 9 or claim 10, wherein the drinking straw is immersed within the contents of the package.

12. A package according to any preceding claim, containing a plurality of internal compartments.

12

13. A package according to any preceding claim, wherein the inner layer comprises more than one line of weakness.

14. A package according to claim 11, comprising perforations substantially perpendicular to the lines of weakness.

15. A package substantially as hereinbefore described, with reference to Figures 7-14 of the accompanying drawings.

16. A process for producing a package according to any preceding claim, comprising the steps of.

(a) bringing a sheet of flexible material into contact with a sheet of material containing a line of weakness; (b) bonding said sheets of material along the length of the line of weakness; (c) preparing a package with said bonded material such that the sheet of material containing a line of weakness forms an inner layer, and the sheet of flexible material forms an outer layer.

17. A process according to claim 16, wherein the line of weakness is a perforated line in the sheet of material, or a zone which is thinner and weaker than the rest of the sheet.

18. A process according to claim 16, wherein the line of weakness is the interface between two abutting strips of material.

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